FMR1 and fragile X syndrome: FXTAS/FXS is also an inherited and unrecoverable neurodegenerative disorder caused by the expansion of tandem repeats of the r(CGG)exp repeats in the 5′ untranslated region (5′UTR) of the Fragile X mental retardation 1 (FMR1) gene, code for fragile X mental retardation protein (FMRP) (47).